Perhaps Thompson, known for his political connections, can help Giuliani tap into more of Illinois' vast reservoir of campaign cash. While Giuliani, with an office in Lisle, boasts the most-visible organization, the former New York City mayor is third in fundraising here.

Arizona Sen. John McCain has collected more than $718,000 and former Massachusetts Gov. Mitt Romney nearly $619,000, better than the $566,000 Giuliani had received from Illinois donors through the end of June.

All three Republicans were dwarfed by the nearly $7 million Democratic Sen. Barack Obama of Chicago raked in and even the $1.7 million Democratic Sen. Hillary Clinton, a Park Ridge native, has tapped in Illinois so far. All fundraising numbers come from Federal Election Commission data analyzed by the Center for Responsive Politics and include contributions of $200 or more.

Giuliani played catch-up Thursday evening at a $1,000-a-person fundraiser at a Lake Forest home where a couple hundred people were expected, according to Ron Gidwitz, Giuliani's Illinois fundraising chairman.

"We're closing the gap," said Gidwitz, a former Republican governor candidate. "We didn't get him as often as we would've liked. His presence helps."

Before chatting up the donors, however, Giuliani toured Mauro Sewer Construction in Des Plaines. Owner Pat Mauro provided sand and generators after last month's flooding.

Stepping out of a Cadillac with Giuliani was Gov. Thompson, who endorsed his fellow former prosecutor for the GOP nomination.

"Rudy Giuliani is the kind of candidate that can appeal to the people of Illinois," Thompson said. "Common-sense solutions to problems and issues facing Americans in this dangerous decade."

Actor and former Sen. Fred Thompson entered the GOP fray this week, but moderate Giuliani brushed aside any suggestion Thompson would take votes away from him as the conservative option.

"I will lower taxes, cut spending, make government more accountable," Giuliani said. "I think that your whole set of views help you win … If we can agree on eight out of 10 things, I'm probably your candidate."

Asked to react to an apparent pending video message from Osama bin Laden on the sixth anniversary of the 9/11 attacks, Giuliani said catching bin Laden "should be a major focus of our government."

"Removing somebody like that, who in a perverse way is very charismatic, could have a big impact in helping us defeat the terrorists in their war on us," he said.

Giuliani was introduced by DuPage County State's Attorney Joe Birkett, who will try to marshal support among law enforcement types for Giuliani.

Also Thursday, Mitt Romney's wife, Ann, traveled to Plano for a fundraiser with about 50 people at the home of former House Speaker Dennis Hastert and his wife, Jean. Before that, Romney stopped by Harry Caray's in Rosemont and had lunch with Dutchie Caray.